相关论文: Dynamical Study of the d(e,e' pi+) reaction
We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/u inpinging on a liquid hydrogen target. Our measurements with HADES confirm a…
We report about the recent results for s- and p-wave pion production in NN -> NNpi within effective field theory and discuss how the charge symmetry breaking in pn -> d pi^0 can be used to extract the strong contribution to the…
The incoherent pion photoproduction reaction gd-->pi-pp is considered theoretically in a wide energy region Eth =< Eg =< 2700 MeV. The model applied contains the impulse approximation as well as the NN- and piN-FSI amplitudes. The aim of…
The two-photon-exchange (TPE) effects in the process $e^+e^- \rightarrow \pi^+\pi^-$ at large momentum transfer are discussed within the perturbative QCD (pQCD). The contributions from the twist-2 and twist-3 distribution amplitudes (DAs)…
Differential cross sections of the reactions $(\gamma,\pi^\circ\pi^\circ)$ and $(\gamma,\pi^\circ\pi^++\pi^\circ\pi^-)$ have been measured for several nuclei ($^1$H,$^{12}$C, and $^{\rm nat}$Pb) at an incident-photon energy of…
We have studied the residual interaction effects theoretically on the deeply bound pionic states in Pb and Sn isotopes. We need to evaluate the residual interaction effects carefully in order to deduce the nuclear medium effects for pion…
Nuclear corrections are presented for neutrino and electron induced reactions in a pedagogical manner. The formalism is demonstrated with numerical studies and is shown to produce substantial corrections in channels where the pions have the…
A model calculation for pion production in nucleon-nucleon collisions is presented. Direct production, pion rescattering and contributions from pair diagrams are taken into account. The amplitudes for the elementary processes are based on…
We show theoretical results for $(\gamma, \pi^0 \pi^0)$ production on nucleons and nuclei in the kinematical region where the scalar isoscalar $\pi \pi$ amplitude is influenced by the $\sigma$ pole. The final state interaction of the pions…
Available data on large-angle nucleon-deuteron elastic scattering $Nd\to dN$ below the pion threshold give a signal for three-body forces. There is a problem of separation of possible subtle aspects of these forces from off-shell effects in…
The similarities in the experimental indications for multinucleon mechanisms in $(\gamma,p)$ and $(e,e'p)$ processes are pointed out. For both types of reactions, the substantial role of two-nucleon emission processes for transitions to…
We analyze the one-photon mechanism of $e^+e^-$ pair production in the collision of nonrelativistic nuclei. The contribution of electric quadrupole radiation of virtual photon to the corresponding cross section is found. The effect of the…
We evaluate the contribution to the nucleon-nucleon interaction due to correlated $\pi\rho$ exchange in the $\pi$, $\omega$, and $A_1$/$H_1$ channels by means of dispersion-theoretic methods based on a realistic meson exchange model for the…
We study the inclusive $(e,e^\prime N)$, $(e,e^\prime NN)$, $(e,e^\prime \pi)$, $(e,e^\prime \pi N)$ reactions in nuclei using a Monte Carlo simulation method to treat the multichannel problem of the final state. The input consists of…
Spin-isospin response in exotic nuclear systems is investigated. It is found that in some nuclei excitations with pionic quantum numbers (0-, 1+, 2-, ...) appear at very low energies with large transition probabilities, which is an…
Some of the recent attempts to detect signals of nucleon-nucleon correlations with semi-exclusive A(e,e'p) and exclusive A(e,e'pN) processes are reviewed. Unfactorized and distorted-wave calculations for these processes are discussed. The…
This is the first of a series of papers on a consistent model independent analysis of the complete experimental information on the reaction $\pi N \rightarrow \pi \pi N$ at pion momenta up to 500 MeV/c. The paper summarizes the theoretical…
High-energy nuclear collisions provide a unique environment for synthesizing both nuclei and antinuclei (such as $\bar{d}$ and $\overline{^4\text{He}}$) at temperatures ($k_BT\sim100$ MeV) nearly two orders of magnitude above their binding…
This report describes the transitions pion -> meson_1 + meson_2 and also pion -> multi-pion for high energy pions interacting with target nuclei (Z,A). The physics interests are: A) Nuclear inelastic coherent diffraction cross sections for…
The influence of final state $NN$- and pi N-rescattering in incoherent pion photoproduction on the deuteron has been investigated. For the elementary photoproduction operator an effective Lagrangian model is used which describes well the…